A new semistructured instrument, the Standardized Polyvalent Psychiatric Interview or SPPI has been developed primarily for assessing medical patients. It has been built on the Clinical Interview Schedule and is intended to evaluate individuals in a multiaxial schema: psychopathology, including duration and severity of disorder; somatic disturbance; social problems and social supports: and pre-morbid personality, with special emphasis on 'neuroticism'. The SPPI generates enough information to allow the use of different research diagnostic criteria, including DSM-III-R, ICD-10 and Goldberg's criteria of 'attribution' of somatic symptoms and 'relationships between psychiatric and physical disorder'. It also includes a section related to recommended treatment. The new interview fulfils standards of feasibility, face and content validity. An incomplete block design, inter-rater reliability study was carried out with a consecutive sample of 48 out-patients referred to the Psychosomatic-Liaison Service of the University Hospital of Zaragoza. A broad range of agreement coefficients were calculated, the results being quite acceptable (most kappas are in the range from 0.7 to 0.9) and tending to support the procedural validity of the interview.